Substantial advances have been made in recent years in the improvement of impact protection for motor vehicle occupants. Various strategies incorporating active and passive restraint systems have been implemented in motor vehicles. Sophisticated energy absorbing structures are designed into motor vehicles with an eye toward reducing occupant injuries.
While much progress has occurred in improving the safety of motor vehicle occupants in impact conditions, one segment of victims of motor vehicle impacts has been largely unaddressed; namely, pedestrians. Motor vehicle impacts with pedestrians remain a serious concern, taking the lives of many each year throughout the world and causing severe injuries.
Certain strategies are known to reduce the severity of pedestrian impacts. For example, it is known in the art to provide a motor vehicle with a front hood that raises a predetermined distance to provide for energy absorption in anticipation of a vehicle impact with a pedestrian. However, in order to take advantage of such hood lifting technologies, the vehicle must be designed such that the hood must not rise above a predetermined height. Otherwise, the hood lifting approach does not benefit typical pedestrians. Moreover, shorter pedestrians, including children, receive little benefit from hood lifting systems which are designed to reduce the severity of impact of the upper body of the pedestrian as a pedestrian's body is rotated by the initial impact with the lower torso.
Another technology for addressing pedestrian impacts has further been proposed which incorporates an inflatable energy absorbing structure deployed from the front end of the vehicle based on an anticipated impact. This approach has a substantial disadvantage that it must be deployed in an irreversible process in response to a detected impending impact. This requirement imposes significant design and cost penalties.
It is also known in the art to provide an extendable-type bumper arrangement for vehicles which, in anticipation of an impending vehicle crash, or in response to a predetermined speed threshold, will extend a predetermined distance from an unextended position. However, it is noted that such extendible-type bumper arrangements are designed to protect either the vehicle occupants or the vehicle. It is noted that in order to attenuate the energy of a first vehicle striking a second vehicle or the like, the energy absorption requirements are substantially different than would be optimal to attenuate the energy of a vehicle impacting a pedestrian with an aim toward reducing injury to the pedestrian. In fact, it should be recognized that most of the extendible bumper-type approaches for vehicle impact protection may pose a risk of greater harm to a pedestrian than a conventional bumper.
It is the lack of protection for pedestrians and, in particular, shorter pedestrians in combination with high hoods and the need for pre-crash human discrimination sensing and non-pedestrian friendly extended bumpers that are addressed by the present invention. This invention provides an improved pedestrian protection apparatus. The apparatus has particular use in mitigating harm otherwise caused to pedestrians when struck by an automotive vehicle. The invention incorporates a grill covering of the front end structure of a vehicle which is actuated to extend from the vehicle exterior based on commands from an electronic control unit.
Various strategies for deployment of the system of this invention may be implemented. For example, merely by sensing the speed of the vehicle, the grill could be automatically extended without intervention by a vehicle occupant whenever the vehicle is moving at city traffic speeds which would be typical in instances of pedestrian impact. The actuators for the grill may be designed to have energy absorbing characteristics, thus providing an energy absorbing “soft” grill structure which strikes the pedestrian. The extended position of the grill allows substantial energy absorption to occur, reducing pedestrian injuries. The extended grill may also secondarily act as a sensor for vehicle impacts. In the extended position, an impact load acting on the grill can be used to deploy additional pedestrian impact mitigation systems, such as hood lifting technology or inflatable energy absorbing structures.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.